Different types of OCV and measures

[vikramc98406]

native ocv

Can someone share the below info

What are different types of OCV?
How does it effect Setup and Hold?
What measures do we have to take resolve these issues?

Any body heard of AREA OCV.

Pls point me to helpful info.

 

[santhosh007]

set_timing_derate -cell_checks

Can someone share the below info

What are different types of OCV?
How does it effect Setup and Hold?
What measures do we have to take resolve these issues?

Any body heard of AREA OCV.

Pls point me to helpful info.

I didnt heard about different types of OCV. but, you can different ocv margins for the designs. let say instead of applying 10% margin as a ocv for across the design,
you can have variable ocv margins for clock and data path. Even you can have ocv margin based on the no of elements in that particular path.

 

[hiral.kotak]

location based ocv

Hi,

As per my knowledge I came across two types of OCV analysis:
(1) Margin based OCV
(2) Native OCV (Marginless OCV)

Thanks..

HAK..

 

[raju3295]

ocv margins

hi hiral.
can you elaborate on Marginless OCV

 

[hiral.kotak]

say about the different types of margin

Hi,

In the marginless ocv the tool doesn't calcuate the ov margin as per the derating factors for the path, so it will take less run time compared to the normal ocv analysis. Will send you the doc for the same.

It may help you.

Thanks..

HAK..

 

[raju3295]

derate ocv

hi hiral
if there are no derating factors,,, whts the difference in the normal analsis like bcwc and ocv,,,

 

[no_mad]

derating in clock reconvergence

Hi Hiral,

Need you help.
Pls explanation on this marginless ocv concept?
I'm very interested to hear from you on this topic.

Because i came across a PT design constraint was set for OCV but no derating factor.
I have a lot of questions and doubts.

My concern is how PT calculate and analyze one timing path? What about clock reconvergence pessimism?

Are there any diff between these 2 setting below (margin-less ocv)
1) set_timing_derate (NOT defined) & timing_remove_clock_reconvergence_pessimism is set to true

2) set_timing_derate (NOT defined) & timing_remove_clock_reconvergence_pessimism is set to false

Please help me out here. I'm confuse.
Highly appreciate.

 

[hiral.kotak]

calculate ocv derating

Hi,

According to me this is the one difference between margin based and native ocv.
Pls find the attached doc.

It may help you.

Thanks..

HAK..

 

[vikramc98406]

Thanks, hiral.kotak

Just to brief the doc says

In Margin Base OCV, tool will consider worst OCV derated margin for all the end points paths
In MarginLess OCV, tool will consider actual OCV derated margin foreach end pointspaths

Thanks

 

[honeysinghpurba]

Thanks buddies now i understand the concept of OCV